Photolithography is the patterning technique at the foundation of microfabrication, the core of modern integrated circuit technology. In a photoresist, the pattern of optical irradiation is converted to a pattern of chemically distinct regions, typically through photoinitiated functional group cleavage or crosslinking. Many modern photoresists employ the concept of “chemical amplification,” in which a photogenerated catalyst reacts with many sites. For example, photoacid generators are commonly employed in chemically amplified resists, either to catalyze a ring opening polymerization or initiate a cascade of deprotective bond scissions within a polymer matrix, imparting new solubility properties to the irradiated regions. While there are a number of light-mediated reactions that could be, in principle, employed in photolithography, very few have been implemented. Despite the fact that there are hundreds of commercially available photoresists, the functional diversity amongst these materials is severely limited. In most applications, the photoresist serves the sole purpose of a sacrificial mask or mold; very rarely is the resist material incorporated as a structural element or chemically functional interface. The ability to generate new kinds of chemically functional materials directly via photolithography would enable a host of new applications, for example in microelectromechanical systems (MEMS), microfluidics, patterned biomaterials and artificial optical materials. Olefin metathesis is a robust synthetic methodology that has led to new polymeric materials with many applications, such as drug delivery, organic electronics, and photonic crystals.